Noncircular head joint for a concert flute and method of manufacture

ABSTRACT

A noncircular flute head joint having superior tone quality is manufactured by forming two substantially identical half sections, each defined by a generally smooth, continuous, half closed curvilinear wall extending longitudinally between a connecting end and a closure end with a smooth, gradual transition along the longitudinal direction from semicircular at the connecting end to nonsemicircular at the closed end, bonding the two half sections into facing mating relationship with the two connecting ends disposed opposite one another, forming a blow hole through the wall near the closure end, and closing the interior of the head joint between the blow hole and the closure end. The resulting head joint has a curvilinear, longitudinally extending closed wall with a tapered interior cross section which may have a smooth transition from circular to an ojival or quasielliptical shape defined by the intersection of two circles. Placement of the blow hole at a circle intersection permits increased control over the depth of the leading and chin edges of the blow hole for better adaptation of the flute head to the particular embouchure characteristics of a given musician.

United States Patent [1 1 Eajardo Feb. 18,1975

l l NONCIRCULAR HEAD JOINT FOR A CONCERT FLUTE AND METHOD OF MANUFACTURE [76] Inventor: Raoul J. Eajardo, PO. Box 4194,

Whittier, Calif. 90605 [22] Filed: July 26, 1973 21 Appl. No.: 382,867

[52] US. Cl. 84/384 [51] Int. Cl. GlOd 7/02 [58] Field of Search 84/384 [56] References Cited UNITED STATES PATENTS l,6l8,892 2/1927 Skinner 84/384 3,685,388 8/1972 Young 84/384 Primary Examiner-Lawrence R. Franklin Attorney, Agent, or FirmFraSer and Bogucki I57] ABSTRACT A noncircular flute head joint having superior tone quality is manufactured by forming two substantially identical half sections, each defined by a generally smooth, continuous, half closed curvilinear wall extending longitudinally between a connecting end and a closure end with a smooth, gradual transition along the longitudinal direction from semicircular at the connecting end to nonsemicircular at the closed end, bonding the two half sections into facing mating relationship with the two connecting ends disposed opposite one another, forming a blow hole through the wall near the closure end, and closing the interior of the head joint between the blow hole and the closure end. The resulting head joint has a curvilinear, longitudinally extending closed wall with a tapered interior cross section which may have a smooth transition from circular to an ojival or quasi-elliptical shape defined by the intersection of two circles. Placement of the blow hole at a circle intersection permits increased control over the depth of the leading and chin edges of the blow hole for better adaptation of the flute head to the particular embouchure characteristics of a given musician.

12 Claims, 8 Drawing Figures PATENTEU FEB I 8M5 SHEET 1 BF 2 PATENTED FEB l 8 I975 SHEET 2 BF 2 NONCIRCULAR HEAD JOINT FOR A CONCERT FLUTE AND METHOD OF MANUFACTURE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a musical instrument head joint and method of manufacture and more particularly to a Boehm concert flute head joint having a smooth transition from a circular interior cross section at a connecting end to a noncircular interior cross section at a closure end and an asymmetrical embouchure hole.

2. History of the Prior Art One popular wind type of musical instrument has come to be known as the Boehm or concert flute. The Boehm flute traditionally includes a head joint which is detachably connected to a body portion having fingering holes and keys thereon. The head joint has a circular cross section which is smoothly tapered from a relatively large diameter at the connecting end to a smaller diameter at the opposite end which is normally closed by a cork. While the internal diameter traditionally has a parabolic taper, modern manufacturing techniques have often produced a metallic head joint having a linear taper. A symmetrical embouchure hole located near the closure may have a circular, elliptical or square with radiused corners cross section and an embouchure plate is conventionally affixed to the head joint at the embouchure hole to provide a desired increased depth therefor.

A conventionally constructed Boehm flute has several undesirable limitations. With such a flute the frequency range is limited to approximately three octaves and it is difficult to avoid a harsh metallic sound when playing notes in the upper portion of this range. It is particularly difficult to avoid this harsh metallic sound when playing a loud, high note, with a flute of inexpensive metal. In addition, because of manufacturing difficulties, an approximately parabolic taper is seldom available in commercial flutes. The manufacture of wooden or non-metalic is particularly uneconomical because of the requirement for expensive boring tools which must be frequently replaced.

SUMMARY OF THE INVENTION The method of manufacturing a musical instrument head joint in accordance with the invention includes the steps of forming two substantially identical half sections, each defined by a generally smooth continuous wall extending longitudinally between a connecting end and an opposite closure end with a half closed curvilinear interior cross section which is semicircular at the connecting end and has a gradual, continuous transition to a nonsemicircular interior cross section at the closure end, bonding the two half sections into facing mating relationship with the connecting ends disposed opposite one another to form a hollow head joint having a circular interior cross section at the connecting end, forming an aperture in the wall near the closure end and closing the head joint between the closure end and the aperture.

The two half sections may be formed by separating a length of circular phenolic tubing having a longitudinal central axis into two substantially identical semicircular half sections with the separation occuring along a diametric plane passing through the central axis, and chamfering each half section along a chamfer plane intersecting the diametric plane at a connecting end along a line passing through the central axis perpendicular thereto. Because of the non-circular shape, placement of the embouchure hole in the vicinity of the intersection permits a wide selection of leading and chin wall depths by selectively varying the exact location and angle of the hole. The non-circular shape also permits the head joint to vary in thickness both longitudinally and circumferentially while retaining a uniform thickness in a direction radial to the wall curvature. The variation in thickness can be controlled by varying the chamfer depth.

Alternatively. the two half sections may be formed by molding them in a desired shape. The interior wall surface should have a cross section which varies smoothly and continuously from a semicircular cross section at the connecting end to a nonsemicircular cross section of less enclosed area at the closure end.

It has been found that flute heads in accordance with this invention exhibit greatly improved tone color and playing characteristics throughout a full dynamic range over extended frequencies when an optimum taper is chosen in accordance with material and wall thickness. The full, rich tone can be dynamically varied between very soft and very loud in a bi-directional manner with no special effort required to prevent the sound from breaking off. Even in the higher registers, including frequencies not normally attainable with a conventional flute, the harsh, metallic sound frequently produced by a conventional head joint is easily avoided.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the invention can be had from a consideration of the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. I is a top view of a non-circular cross-sectioned flute head joint in accordance with the invention;

FIG. 2 is a sectional side view of the flute head joint shown in FIG. 1, taken along the line 2-2 in the direction of the arrows;

FIG. 3 is an end view of the flute head joint shown in FIG. I taken from the connecting end:

FIG. 4 is an end view ofthe flute head joint shown in FIG. Ltaken from the closure end;

FIG. Sis a top view of a portion of the flute head joint shown in FIG. 1 illustrating a step in the manufacturing process;

FIG. 6 is a cross-sectional view of the flute head shown in FIG. 1 taken along line 66 in the direction of the arrows and illustrating one arrangement of an embouchure hole in accordance with the invention;

FIG. 7 is an alternative arrangement of the embouchure hole shown in FIG. 6; and,

FIG. 8 is another alternative arrangement of the embouchure hole shown in FIG. 6.

DETAILED DESCRIPTION As illustrated in FIGS. 14 to which reference is now made, a non-circular flute head joint 10 defined by a circumferentially closed, curvilinear wall 12 extending longitudinally between a connecting end 14 at which the flute head joint I0 may be connected to a flute body (not shown) and a closure end 16. A circumference of head joint 10 extends around a longitudinal central axis I8. The interior of wall I2 in transverse cross sections along planes perpendicular to axis I8 vary with a smooth, gradual, continuous transition from circular at the connecting end I4 (See FIG. 3) to non circular at the closure end 16 (See FIG. 4), the enclosed area ofthe interior cross section being less at the closure end 16 than the connecting end 14. An embouchure hole 20 having a central axis 22 is formed in the wall 12 near the closure end 16 and a closure element which may be a cork plug 24 is disposed at a selected location between the embouchure hole 20 and the closure end 16. A tenon 28 is received by a counter bore 30 at the connecting end 14 of the head joint which is concentric with central axis 18. The external surface of the wall 12 is formed into a cylindrical shaft 32 which receives an annular reinforcing ring 34.

The head joint 10 is formed by bonding two half sections, 36, 38 in facing mating relationship. The half sections 36, 38 are substantially identical and may be formed in an identical manner by separating a length of phenolic tubing about 18.2 cm long into two substantially identical semi-circular half sections. While the particular material of the tubing is not critical, it does affect the tone color. Linen phenolic plastic, paper phenolic plastic and wood have been found to provide desirable sounds. Manufacture of the head joint 10 from paper phenolic tubing has produced an instrument with a particularly rich sound. A sound similar to that of a baroque flute which is desirable for playing chamber music was easily attained by connecting such a head joint to a standard metal concert flute body having the advantages of a standard Boehm fingering system. In one desirable arrangement the tubing has an inside diameter of 1.90 cm and an outside diameter of 2.80 cm. The wall thickness is substantially uniform throughout.

Phenolic tubing has physical properties somewhat similar to wood and may be worked by sawing, cutting, carving, sanding, grinding, and by other conventional wood working techniques. As illustrated by the half section 36 shown in FIG. 5, the length of tubing is separated into two half sections 36, 38 by sawing longitudinally along a diametric plane 40 passing through a longitudinal central axis 42 which will become concentric with the axis 18 at the connecting end when the two halves 36, 38 are assembled. I-Ialf section 38 is not separately shown in the drawings but it will be appreciated that it may be manufactured in a manner substantially identical to that of half section 36.

The half section 36 is beveled or chamfered at the diametric plane 40 until the curvilinear wall 44 which forms a portion of wall 12 when the manufacturing process is completed, terminates in a chamfer plane 46 which intersects the diametric plane 44 along a line 48 (see also FIG. 3) which passes through the central axes 18, 42 perpendicular thereto at the connecting end 14. The interior wall surface 50 of chamfered half section 36 has a half closed curvilinear cross section perpendicular to the central axis 42 which is semicircular at the connecting end 14 and gradually changes in a smooth continuous manner to a mon-semicircular cross section at the closure end 14 (See FIG. 4).

The half section 36 is preferably chamfered to a depth of about 0.225 cm at the closure end. As illustrated in FIG. 4 this results in an ojival or quasielliptical cross section formed by the intersection of two circles when the two half sections 36, 38 are assembled and bonded in mating facing relationship. The interior cross-sectional area is somewhat smaller at the closure end 16 than at the connecting end 114 as a result of the chamfering operation.

The half sections 36, 38 may alternatively be manufactured by other manufacturing processes such as by molding or by casting. In such a case a complete head joint may be produced in one single operation. However, in any event, the interior surface of the head joint must be circular at the connecting end 14 and noncircular at the closure end 16. It has been found that the phase shift and relative strength of the harmonics are favorably affected by the noncircular cross section.

After chamfering, the half sections 36, 38 are assembled and bonded into facing mating relationship with the semicircular connecting ends disposed opposite one another to form circular interior and exterior cross sections at the connecting end 14. The embouchure hole 20 may then be formed near the closure end 16 taking selective advantage of the increased thickness of the wall 12 at the intersection of the ojive defining circles which results from the center of curvature of the wall 12 being displaced from the central axis 18 because of the chamfering operation. The axis 22 of hole 20 is desirably placed approximately 1 1.7 cm from the connecting end 14.

Thus, as illustrated in FIGS. 3 and 4, the wall 12 of head joint 10 has a substantially uniform thickness in a direction perpendicular to a line 57 which is tangent to a point of measurement. However, except at the connecting end 14, thethickness is nonuniform and varies over at least part of the circumference in a direction radial to the central longitudinal axis 18 as illustrated by radius 58. This phenomenon occurs because the chamfering of half sections 36, 38 eliminates the coincidence between the center of curvatures of wall 12 and axis 18 away from the connecting end 14. The difference is accentuated along the longitudinal direction as the closure end 16 is approached and along a circumferential direction as a mating intersection of the half sections 36, 38 is approached.

As shown in FIG. 6 the central axis 22 of embouchure hole 20 passes through the chamfer plane 46 perpendicular to the central axis 18. This arrangement results in a leading edge 54 having a depth substantially equal to an opposite chin edge 56. The leading edge 54 and chin edge 56 are substantially parallel at their widest point of cross-sectional separation.

Alternatively, as shown in FIG. 7, an embouchure hole having a central axis 62 may be disposed with a chin edge 64 oriented substantially radially with respect to the radius of curvature of the wall 12 to obtain minimum thickness. The leading edge 66 has an intermediate depth or thickness in this arrangement.

Still another arrangement is illustrated in FIG. 8. In this arrangement an embouchure hole 70 has a central axis 72 oriented to make the cross-sectionally widest portion of a leading edge 74 extend substantially radially with respect to the curvature of the wall 12 thereat. Simultaneously, the hole 70 is disposed laterally with the axis eccentrically disposed with respect to the chamfer plane 46 and a chin edge 76 is properly oriented (not necessarily parallel to the leading edge 74) to intersect the interior surface of the wall 12 substantially tangentially. This arrangement results in a leading edge 74 of minimum depth and a very deep chin edge 76 formed by substantially the entire interior surface of half section 36 in the longitudinal vicinity of the hole 70.

FIGS. 7-8 are intended to be only exemplary of the infinite combinations of embouchure edge depths and orientations which are attainable with head joints in accordance with this invention to attain particular embouchure characteristics which facilitate the maintenance of proper intonation. Furthermore, because of this ability to control the effective depth of the embouchure hole, the need for an embouchure plate as required for a conventional flute head is eliminated. Alternatively, an embouchure plate may be provided if the head joint is made of relatively thin walled material. A slight concavity 80 shown in FIG. 1 may be formed adjacent the embouchure hole which allows the musician to more accurately feel the correct position of the embouchure hole.

As further shown in FIG. 1, the symmetrical hole 20, as well as the nonsymmetrical holes 70 may have a novel shape in a cross-sectional plane perpendicular to the central axis 22. The hole 20 is symmetrical about a transverse plane passing through axis 22 perpendicular to axis 18, but is asymmetrical with respect to a longitudinally extending plane passing through axis 22. The hole 20 has a circular cross-sectional shape along the chin edge 56 in half section 36 on one side of the longitudinal plane and an elliptical cross-sectional shape along leading edge 54 in half section 38 on the opposite side of the longitudinal plane through axis 22.

It has been found that a head joint having an ojival or quasi-elliptical body cross section and an embouchure hole positioned at the intersection of the ojive defining circles as taught herein with a semi-elliptical leading edge and a semicircular chin edge has an improved frequency range. For instance, very high notes such as D three octaves above the lowest D of the standard Boehm flute is attained with much greater ease than with a standard Boehm flute, even without a metal construction.

Manufacture of the head joint may be complete as shown in FIGS. 1 and 2 by counter boring the connecting end 14 to a depth of about 1.4 cm and inserting the 5.3 cm long tenon 28 within the resulting counter bore 30. The tenon may have an inside diameter of 1.90 cm and an outer diameter of 1.98 cm for proper coupling to one commercially available flute body. The external surface of wall 12 may be rounded and reduced in diameter to form a shoulder 32 which receives the reinforcing annular ring 34 in abutting relationship. The ring 34 reinforces the wall 12 at the region of high stress where the tenon 28 is bonded to the head joint 10 in telescoping mating relationship. The exterior corner may then be chamfered at the connecting end 14 to provide a smoother, more esthetic transition between the relatively thick head joint 10 and a typically much thinner standard metal flute body (not shown).

Manufacture of the flute head joint 10 is then completed by disposing a closure element such as a cork plug 24 to form a closure surface between the embouchure hole and the closure end 16. The closure surface is typically located 1.35 cm from the central axis 22 of the embouchure hole 20, but the exact distance is dependent upon the particular tuning characteristics of a given head joint.

While there have been described above various arrangements and methods of manufacture for a musical instrument head joint in accordance with the invention for the purpose ofillustrating how the invention may be used to advantage, it will be appreciated that the invention is not limited thereto. Accordingly, any modification, variation or equivalent arrangement within the scope of the appended claims should be considered to be within the scope of this invention.

What is claimed is:

l. A head joint for a concert flute comprising a curvilinear closed wall having a connecting end and a longitudinally spaced closure end, the interior surface of the closed wall defining a cross section in a plane perpendicular to the longitudinal direction which has a gradual, continuous transition from circular at the connecting end to approximately elliptical at the closure end; and an embouchure hole extending through the wall and having a central axis longitudinally disposed nearer the closure end than the connecting end.

2. The head joint as set forth in claim 1 above wherein said cross section is defined by two intersecting circles at the closure end and wherein the embouchure hole is disposed at an intersection of two defining circles.

3. The head joint as set forth in claim 2 above. further comprising aclosure element disposed to close the interior of the head joint between the blow hole and the closure end.

4. The head joint as set forth in claim 1 above, wherein the curvilinear closed wall is fabricated from paper phenolic plastic.

5. The head joint as set forth in claim 1 above, wherein the curvilinear closed wall is fabricated from linen phenolic plastic.

6. The head joint as set forth in claim 1 above, wherein the curvilinear closed wall is fabricated from wood.

7. A generally tubular musical instrument head joint having a central longitudinal axis, a circumference extending around the longitudinal axis, opposite connecting and closed ends, and an embouchure hole having a central axis longitudinally disposed nearer the closed end than the connecting end, the head joint having a transverse cross-sectional shape around a circumference near the embouchure hole defined by a curvilinear wall having interior and exterior surfaces and having a a substantially uniform thickness along the circumference in a direction perpendicular to a tangent to a point of measurement on the interior wall and a nonuniform thickness in a direction radial to the central longitudinal axis which varies with circumferential position over at least part of the circumference.

8. The instrument head joint as set forth in claim 7 above, wherein the embouchure hole is circumferentially disposed at a region of variable thickness in a direction radial to the central longitudinal axis.

9. The instrument head joint as set forth in claim 7 above, wherein the embouchure hole is defined by a leading edge on one side of a longitudinally extending plane passing approximately through a central axis of the embouchure hole and a chin edge of the opposite side of the plane and wherein the embouchure hole is selectively oriented and positioned within the region of variable thickness to provide desired different thicknesses for the leading and chin edges.

10. The instrument head joint as set forth in claim 9 above, wherein the leading edge has a generally ellipti cal shape about the central axis and the chin edge has a generally circular shape about the central axis.

11. A generally tubular musical instrument head joint having a central longitudinal axis comprising a pair of substantially identical half sections of tubing which are chamfered along a plane which intersects the longitudiclaim 11 above, wherein the embouchure hole has a selectively oriented central axis, has a leading edge and a chin edge, and is circumferentially disposed to be intersected by the chamfer plane, said circumferential disposition and central axis orientation being chosen to provide desired different thicknesses for the leading and chin edges.

UNITED STATES PATENT OFFICR CERTIFICATE OF CORRECTION PATENT NO. 3 ,866 ,507 DATED February 18, 1975 INVENTOR(S) Raoul J Fajardo it is certrfied that error appears in the above-identrtied patent and that said Letters Patent are hereby corrected asshown betow' On the cover sheet, under "United States Patent [19]" "Eajardo" should read --Fajardo--; after '[76] Inventorz" "Raoul J. Eajardo" should read --Raoul J. Fajardo--.

Col. 2, line 69, after "the", "connecting" should read -closure--. Col. 3, line 14, after "tions" delete the comma line 57, "men-semicircular" should read --non-semicircular-- Signed and Sealed this twenty-third D a} Of September 19 75 [SEAL] A [res]:

RUTH C. MASON .-1 running Officer C. MARSHALL DANN ('ummrlm'nm'r (If lurcnlx and Trademarks UNITED STATES PATENT OFFICR CERTIFICATE OF CORRECTION PATENT NO. 3 866 507 DATED February 18, 1975 INVENTOR(S) Raoul J. Fajardo it is certrtted that error appears in the ah0ve-ident|fied patent and that said Letters Patent are hereby corrected as shown below On the cover sheet under "United States Patent [19] "Eaj ardo" should read --Faj ardo-- after "[76 Inventor "Raoul J. Eajardo" should read Raoul J. Fajardo--. Col 2 line 69, after "the", "connecting" should read --closure- Col 3 line 14 after "tions de le te the comma line 57 "mom-semicircular" should read --non-semicircular-- Signed and Sealed this twenty-third D 3y OF September 19 75 [SEAL] A Nest.

RUTH C. MASON ,1 Nesting Officer C. MARSHALL DANN ('mnmrlrsimrcr of Parents and Trademarks 

1. A head joint for a concert flute comprising a curvilinear closed wall having a connecting end and a longitudinally spaced closure end, the interior surface of the closed wall defining a cross section in a plane perpendicular to the longitudinal direction which has a gradual, continuous transition from circular at the connecting end to approximately elliptical at the closure end; and an embouchure hole extending through the wall and having a central axis longitudinally disposed nearer the closure end than the connecting end.
 2. The head joint as set forth in claim 1 above wherein said cross section is defined by two intersecting circles at the closure end and wherein the embouchure hole is disposed at an intersection of two defining circles.
 3. The head joint as set forth in claim 2 above, further comprising a closure element disposed to close the interior of the head joint between the blow hole and the closure end.
 4. The head joint as set forth in claim 1 above, wherein the curvilinear closed wall is fabricated from paper phenolic plastic.
 5. The head joint as set forth in claim 1 above, wherein the curvilineAr closed wall is fabricated from linen phenolic plastic.
 6. The head joint as set forth in claim 1 above, wherein the curvilinear closed wall is fabricated from wood.
 7. A generally tubular musical instrument head joint having a central longitudinal axis, a circumference extending around the longitudinal axis, opposite connecting and closed ends, and an embouchure hole having a central axis longitudinally disposed nearer the closed end than the connecting end, the head joint having a transverse cross-sectional shape around a circumference near the embouchure hole defined by a curvilinear wall having interior and exterior surfaces and having a a substantially uniform thickness along the circumference in a direction perpendicular to a tangent to a point of measurement on the interior wall and a nonuniform thickness in a direction radial to the central longitudinal axis which varies with circumferential position over at least part of the circumference.
 8. The instrument head joint as set forth in claim 7 above, wherein the embouchure hole is circumferentially disposed at a region of variable thickness in a direction radial to the central longitudinal axis.
 9. The instrument head joint as set forth in claim 7 above, wherein the embouchure hole is defined by a leading edge on one side of a longitudinally extending plane passing approximately through a central axis of the embouchure hole and a chin edge of the opposite side of the plane and wherein the embouchure hole is selectively oriented and positioned within the region of variable thickness to provide desired different thicknesses for the leading and chin edges.
 10. The instrument head joint as set forth in claim 9 above, wherein the leading edge has a generally elliptical shape about the central axis and the chin edge has a generally circular shape about the central axis.
 11. A generally tubular musical instrument head joint having a central longitudinal axis comprising a pair of substantially identical half sections of tubing which are chamfered along a plane which intersects the longitudinal axis at a connecting end, the chamfered half sections being secured in mating relationship along a chamfer plane to form a cross sectional shape in a plane perpendicular to the longitudinal axis which is circular at a connecting end and which has the shape of two intersecting circles at a closure end, the head joint having an embouchure hole therethrough at a position nearer a closure end than a connecting end.
 12. The musical instrument head joint as set forth in claim 11 above, wherein the embouchure hole has a selectively oriented central axis, has a leading edge and a chin edge, and is circumferentially disposed to be intersected by the chamfer plane, said circumferential disposition and central axis orientation being chosen to provide desired different thicknesses for the leading and chin edges. 